Chrys. I had the same problems. Can you check and see what version of BBM is on your Tour now. 4.7.1 or 4.7.0. Mine was 4.7.0. Im not sure which fixed my Tour, but I used the 4.7.0 files from the storm and loaded them in the C:\Program Files\Common Files\Research In Motion\Shared\Loader Files\9630-v4.7.1.40_P4.1.0.40 directory. Its worth a shot.

Make sure and delete vendor.xml file in c/program files/common files/research in motion/app loader and scroll down to bottom, for OS from different carrier. Oh, and don't forget to back up first, both phone and 3rd party apps.

once it's loaded on the PC ( takes about 20-30minutes) follow this path
c: program files > common files > research in motion > apploader - at the bottom of the list you should see a file called a vendor file - delete that. reboot pc

reopen c: program files > common files > research in motion > now go to shared > loader - place it here

go back to BBM5 file and select every other file and place them in here;
c: program files > common files > research in motion > now go to shared > loader - open your os and open the java folder and right click paste 0 over write all files

NOW YOUR DONE INSTALLING BBM5.0

now we load--- go to c: program files > common files > research in motion > apploader and with your device pluged in open the apploader icon (looks like a little phone) follow the steps but make sure you put a checkmark beside any of the apps in the list you want to be placed back onto your device.

reopen c: program files > common files > research in motion > now go to shared > loader - place it here

go back to BBM5 file and select every other file and place them in here;
c: program files > common files > research in motion > now go to shared > loader - open your os and open the java folder and right click paste 0 over write all files

My Research In Motion folder doesnt contain the folders Shared, Loader, or Java, can I just create them?